Conventional tillage implements (e.g., cultivators, disks, ploughs, chisels, and harrows) are used in a variety of different field conditions and for a variety of different purposes. Some tillage implements are specially configured to operate at high speeds and shallow depths, while other tillage implements are configured for lower speeds and deeper depths. Additionally, some tillage implements are configured to effectively traverse rough or rolling terrain, while other tillage implements are configured to operate on relatively flat ground. Often a single farming operation encounters a variety of conditions that force the farming operation to either purchase multiple types of tillage implements or to operate a single tillage implement in a less than ideal manner. Accordingly, there exists a need for a tillage implement that is effective in a variety of different field conditions and for a variety of different purposes.
The present invention provides a tillage implement that is particularly effective in avoiding the placement of untoward stresses and strains on the implement frame and other critical components of the machine as the machine traverses rough, uneven, or rolling terrain during field operations or transport to and from the field. Ground-engaging wheels of the machine are raised and lowered in unison for lifting or lowering the main frame of the machine, but in one preferred embodiment a pair of front wheels that share a portion of the load of the machine's frame can operate in a non-corresponding manner when the terrain encountered by one of the wheels differs significantly from that encountered by the other. The wheels are linked to one another in such a manner that they can shift upwardly or downwardly relative to one another in equal amounts but in opposite directions so as to maintain both wheels touching the ground and the load of the frame equalized on both of the wheels notwithstanding significant differences in the terrain under the wheels. This avoids concentrating the load on only one of the wheels, for example, such as could occur if the wheels were both locked at a fixed height relative to the frame and one of the wheels were to roll over a high spot that raised the frame and caused the other wheel to be lifted completely off the ground.